Both titles can be consider (in some way) as a classic , "must-watch" anime. Those surreal stories focus on life, death, sense of existence. Slowly, patient atmosphere, fantasy elements, journey - both animes intrigue in similar way

Heavy symbolism that can be interpreted in several ways? Check!
Visually different from the norms of anime? Check!
Christian undertones? Check!
Complex enough to almost necessitate re-watches? Check!
In short, Angel's Egg and Night on the Galactic Railroad are incredibly similar in themes and visual approach. They both cause insane amounts of discussion (are they intelligent and symbolic or just incomprehensive for the sake of it) and if you liked one you're likely to enjoy the other. Unless you mind strong christian symbolism that is.